Because of the recent electrical motorization of vehicles, vehicles using motors as rotational driving sources are increasing. In the case where motors are used as rotational driving sources, noise is produced in rotors constituting the motors and transmitted to knuckles through a driveshaft, and is further externally radiated to cause radio noise. For example, an antenna of an in-vehicle radio picks up the above noise to produce the radio noise.
As a countermeasure to the radio noise as above, according to Patent Literature 1, the radio noise is dissipated to the vehicle body side for preventing the external radiation of the radio noise, by grounding realized by electrically connecting a parking brake wire and a carrier which is arranged rotatably relative to the axle.